1. Technical Field
The present invention relates to a lighting device which includes a luminous element such as an organic EL (Electroluminescence) element or the like, the manufacturing method thereof, and an electronic apparatus including the device.
2. Related Art
In recent years, a lighting device which includes an organic EL element has been developed. Since the thickness of the light-emitting layer of the organic EL element, which is a self-luminous element, is extremely thin, it is possible to make the lighting device light and thin when the organic EL element is applied to the lighting device. In addition, since the organic EL element is able to emit light of high luminance in a low voltage, it is also possible to achieve power savings in the lighting device. In this manner, since it is possible to make the lighting device in which the organic EL element is used thin and be able to save electric power, the lighting device may be also mounted in a liquid crystal display or portable device which needs to be thin and light, in addition to lighting device such as a lamp.
The organic EL element is configured by a light emitting functional layer and two electrodes, a positive electrode and a negative electrode, which pinch the light emitting functional layer from both sides. However, when the light emitting functional layer deteriorates with time, or a conductive foreign substance enters the light emitting functional layer in the manufacturing process, there is a possibility of a short circuit occurring between the two electrodes.
In JP-A-2004-234868, since a plurality of light emitting elements is connected in series, it is possible to make a current continuously flow to the other organic EL element, even if a short circuit occurs in one organic EL element.
However, since a high power supply voltage is necessary for the lighting device in which the plurality of organic EL elements is connected in series as in JP-A-2004-234868, it is necessary to configure a power supply unit using a more pressure resistant element. In addition, when disconnection occurs in the lighting device, there is a problem in that in the lighting device in which the plurality of organic EL elements is connected in series, the entire lighting device is influenced by the disconnection and is turned off.